We have a special cord that has a triple plug to plug the lights into and then the cord extends about another three feet to a miniature tree "ornament" that has a toggle switch on the bottom. This hangs on the tree and makes it very easy to switch the lights on/off without being obvious.

Believe it or not, this was sold by Avon cosmetics about fifteen years ago. They sold it only one year and then withdrew it from the market. I suspect that safety concerns prompted the withdrawal. It has a fairly light weight cord and could easily be overloaded. I never plug more that two strings of lights into it.